Locally-mined ore was mixed with that from nearby Froghall to improve its quality until coke replaced coal as a fuel. The ore from South Wales and the north of England was then used instead.

This continual expansion was to reach its next significant milestone in 1866, with the decision to form a private limited company. On July 10th that year the Shelton Iron and Steel Company Ltd was registered. It had capital of £250,000 in 250 shares each worth £1,000, of which the Earl Granville held 77.

He also held on, very firmly, to the blast furnaces, which continued to operate under his direct ownership.
Although he traded under the name Earl Granville, the two separate sides of the organisation appear to have been operated as one unit.